Spring Tutorials

There are following some steps to create Spring application as given below.

1. Spring 2.5
2. Eclipse IDE
3. JDK 1.6

Step1. Now you create a simple Java Project using Eclipse IDE. Follow the option File -> New -> Project and finally select Java Project wizard from the wizard list. Now name your project as SpringBeanContainer using the wizard window as given below:

Step2. Now add spring jar in your project, To do this, right click on your project name SpringBeanContainer and then follow the following option available in context menu: Build Path -> Configure Build Path to display the Java Build Path window as given below. There are mainly three jar files required to run this application, To load the jar files in eclipse IDE, Right click on your project - Build Path - Add external archives - select all the required jar files - finish.

1. org.springframework.core-3.0.1.RELEASE-A
2. com.springsource.org.apache.commons.logging-1.1.1
3. org.springframework.beans-3.0.1.RELEASE-A

Step3. Now you create simply java file with any name. First we need to create a package with any name like com.r4r. To do this, Right click on src in package explorer section and follow the option : New -> Package. and then Right click on package(com.r4r) - New - class - Write the class name e.g. Employee - finish. Write the following code:

package com.r4r;
public class Employee {
private String name;
private int age;
  public String getName() {  
    return name;  
}  
 public void setName(String name) {  
    this.name = name;  
}  

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}  
}

Employee is simple bean class, containing only two property name and age with its getters and setters method. The name and age of the employee will be provided by the xml file.

Step4. Now create the xml file click on src- new -file -give the file name like r4rBean.xml then finish.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean id="r4rempbean" class="com.r4r.Employee">
<property name="name" value="John Smith"/>
<property name="age" value="25"/>
</bean>
</beans>

The bean element is used to define the bean for the given class. The property subelement of bean specifies the property of the Employee class named name and age. The value specified in the property element will be set in the Employee class object by the IOC container.

Step5.Now Create the java Main class(Demo.java), Here we are getting the object of Employee class from the IOC container using the getBean() method of BeanFactory.

package com.r4r;
import org.springframework.beans.factory.xml.XmlBeanFactory;  
import org.springframework.core.io.ClassPathResource;  
public class Demo {
public static void main(String[] args) {  
XmlBeanFactory factory = 
new XmlBeanFactory(new ClassPathResource("r4rBean.xml"));
Employee employee=(Employee)factory.getBean("r4rempbean");  
System.out.println(employee.getName());  
System.out.println(employee.getAge());
}  
}  

There are following two important points to note about the Demo class:

1. First step is to create factory object where we used framework API XmlBeanFactory() to create the factory bean and ClassPathResource() API to load the bean configuration file available in CLASSPATH. The XmlBeanFactory() API takes care of creating and initializing all the objects ie. beans mentioned in the configuration file.
2. Second step is used to get required bean using getBean() method of the created bean factory object. This method uses bean ID to return a generic object which finally can be casted to actual object. Once you have object, you can use this object to call any class method.

Now run the Application you see the following output